Two “Wonder Vitamins” to Help Immunity

In part five here, I look at the last two vitamins that are linked to boosting one’s immune system. They are vitamins D and E. Vitamin D The most active form of vitamin D — 1, 25-dihydroxycholecalciferol — is a potential regulator of the immune system. Vitamin D receptors have been located in most of the cells in the immune system. 1,25-dihydroxycholecalciferol may protect the lungs from infectious agents by producing powerful immune cells that line the respiratory tract. It has been known for some time that UV radiation from sunlight or artificial sources reduces the incidence of viral and other infections. Vitamin D or sunshine was used to treat patients with tuberculosis in the pre-antibiotic era. Cod liver oil, which contains vitamin D, also reduces respiratory viral infections. In a good-quality study with 104 post-menopausal women given either low dose (800 IU/day) or high dose (2,000 IU/day) vitamin D, those receiving the nutrient were three time less likely to report cold symptoms than those who received placebo. Yet, a more recent trial by the same authors with 162 adults treated with 2,000 IU for 12 weeks failed to show a protective effect of supplemental vitamin D in reducing the incidence or severity of upper respiratory infections during wintertime. Vitamin E As it is a strong antioxidant, vitamin E is able to enhance the immune response. Vitamin-E supplements raise the lymphocyte production in response to a foreign invader, and increase the body’s resistance to attacks by viral and bacterial infections. As we age, our immune response declines. In one study, vitamin E (200 IU/day) led to a 28% reduction in common cold incidence in subjects older than 65 — especially in older city dwellers who smoked fewer than 15 cigarettes a day. Another reported that vitamin E may have a beneficial or harmful effect, depending on several variables: age; smoking status; and residential neighborhood. In those individuals over 72, vitamin E (200 IU a day) reduced the risk of common cold if they smoked between five and 14 cigarettes a day and lived in cities. That said, vitamin-E supplements actually increased the risk of common cold in those who smoked more than 14 cigarettes a day and were living outside the cities. One randomized, placebo-controlled study had 617 people over age 65 years take either vitamin E (200 IU) or placebo each day. The vitamin-E group experienced a lower incidence of common cold. However, vitamin-E supplements did not reduce lower respiratory tract infections (e.g. pneumonia). The addition of fish oil may in fact blunt the immune-enhancing effect of vitamin E in the elderly.